Paulo Andre de Oliveira of Brazil, Justin Gatlin of the U.S., and Rosangela Santos of Brazil pose at the medal ceremony during the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Paulo Andre de Oliveira of Brazil (L), Justin Gatlin of the U.S. (C), and Rosangela Santos of Brazil pose at the medal ceremony during the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Paralympian Petrucio Ferreira dos Santos of Brazil celebrates after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Paralympian Petrucio Ferreira dos Santos of Brazil celebrates after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Paralympian Yohansson Nascimento of Brazil celebrates after arriving second in the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Paralympian Yohansson Nascimento of Brazil celebrates after arriving second in the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Rosangela Santos of Brazil competes during the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Rosangela Santos (L) of Brazil competes during the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Rosangela Santos of Brazil looks on after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Rosangela Santos of Brazil looks on after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Justin Gatlin of the U.S. runs the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Justin Gatlin (C) of the U.S. runs the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Justin Gatlin of the U.S. celebrates after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Justin Gatlin of the U.S. celebrates after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Justin Gatlin of the U.S. celebrates with Paulo Andre de Oliveira of Brazil after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Justin Gatlin (L) of the U.S. celebrates with Paulo Andre de Oliveira of Brazil after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Justin Gatlin of the U.S. celebrates after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Justin Gatlin of the U.S. celebrates after winning the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Justin Gatlin of the U.S. runs the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Justin Gatlin (C) of the U.S. runs the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil October 1, 2017. REUTERS/Bruno Kelly

Gatlin of the U.S. runs with a child from the Mangueira slum ahead of the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Justin Gatlin of the U.S. runs with a child from the Mangueira slum ahead of the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil, September 29, 2017. REUTERS/Bruno Kelly

Justin Gatlin of the U.S. runs with children from the Mangueira slum ahead of the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro

Justin Gatlin of the U.S. runs with children from the Mangueira slum ahead of the "Mano a Mano" challenge, a 100-meter race, at the Brazilian Jockey Club in Rio de Janeiro, Brazil, September 29, 2017. REUTERS/Bruno Kelly